1. No category

Godfrey A, Lara J, Munro A, Wiuff C, Chowdhury S, Del-Din S, Hickey A,
Mathers J, Rochester L. Instrumented assessment of test battery for physical
capability using an accelerometer: a feasibility study. Physiological
Measurement 2015, 36(5), N71-N83.
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Instrumented assessment of test battery for physical capability using an accelerometer: a
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Institute of Physics and Engineering in Medicine
Physiol. Meas. 36 (2015) N71–N83
Physiological Measurement
doi:10.1088/0967-3334/36/5/N71
Note
Instrumented assessment of test
battery for physical capability using an
accelerometer: a feasibility study
A Godfrey1,2, J Lara3,4, C A Munro3,4, C Wiuff3,4,
S A Chowdhury3,4, S Del Din1,2, A Hickey1,2, J C Mathers3,4
and L Rochester1,2
1
Institute of Neuroscience, Newcastle University, Campus for Ageing and Vitality,
Newcastle upon Tyne, UK
2
Clinical Ageing Research Unit, Newcastle University, Campus for Ageing and
Vitality, Newcastle upon Tyne, UK
3
Institute of Cellular Medicine, Newcastle University, Campus for Ageing and
Vitality, Newcastle upon Tyne, UK
4
Human Nutrition Research Centre, Newcastle University, Campus for Ageing and
Vitality, Newcastle upon Tyne, UK
E-mail: [email protected]
Received 10 November 2014, revised 7 January 2015
Accepted for publication 3 February 2015
Published 22 April 2015
Abstract
Recent work has identified subdomains (tests) of physical capability that are
recommended for assessment of the healthy ageing phenotype (HAP). These
include: postural control, locomotion, endurance, repeated sit-to-stand-to-sit
and TUG. Current assessment methods lack sensitivity and are error prone
due to their lack of consistency and heterogeneity of reported outcomes;
instrumentation with body worn monitors provides a method to address
these potential weaknesses. This work proposes the use of a single tri-axial
accelerometer-based device with appropriate algorithms (referred to here as
a body worn monitor, BWM) for the purposes of instrumented testing during
physicality capability assessment. In this pilot study we present 14 BWMbased outcomes across the subdomains which include magnitude, frequency
and spatio-temporal characteristics. Where possible, we compared BWM
outcomes with manually recorded values and found no significant differences
between locomotion and TUG tasks (p ≥ 0.319). Significant differences were
found for the total distance walked during endurance (p = 0.037) and times for
repeated sit-to-stand-to-sit transitions (p < 0.000). We identified reasons for
Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence.
Any further distribution of this work must maintain attribution to the author(s) and the title of the work,
journal citation and DOI.
0967-3334/15/050N71+13$33.00 © 2015 Institute of Physics and Engineering in Medicine Printed in the UK
N71
Note
Physiol. Meas. 36 (2015) N71
differences and make recommendations for future testing. We were also able
to quantify additional characteristics of postural control and gait which could
be sensitive outcomes for future HAP assessment. Our findings demonstrate
the feasibility of this method to enhance measurement of physical capacity.
The methodology can also be applied to a wide variety of accelerometerbased monitors and is applicable to a range of intervention-based studies or
pathological assessment.
Keywords: accelerometer, instrumented, healthy ageing phenotype,
algorithm
(Some figures may appear in colour only in the online journal)
1. Introduction
The gain in human life longevity observed over recent decades has been accompanied by additional years of poor health (Vaupel 2010, Lara et al 2013). The ability to retain good health
is the foundation to ageing well since poor health disrupts daily life and reduces the ability to
manage the activities of daily living (Black 2009, Parsons et al 2014). Those elements of daily
life which have strong associations with functional capacity can be quantified as an individual’s physical capability (Cooper et al 2010, 2011). Earlier attempts to quantify physical capability used questionnaire based assessments (Townsend 1979, Ware et al 1993). More recently
measures of physical capability include timed tests quantified with a stopwatch such as; chair
rise times, walking speed, timed up and go (TUG) and standing balance that have been shown
to predict health in later life (Cooper et al 2010, Cooper et al 2011). However, quantification
of tasks in this manner requires accurate identification of the beginning/end of a test to be carried out in a reliable and consistent manner across raters which can lead to large heterogeneity
of reported outcomes (Studenski et al 2011). Finally, measurement protocols and reported
outcomes lack consistency making it impossible to pool results (Cooper et al 2011).
As a result the use of electronic devices able to accurately quantify and consistently
record human movement for instrumented testing has steadily risen in recent years (Godfrey
et al 2008, Narayanan et al 2010, Weiss et al 2011, Mancini et al 2012, Mellone et al 2012,
Godfrey et al 2014). Instrumented testing is not limited to any patient group, is not biased by
age or gender differences and can provide highly accurate and objective data (Godfrey et al
2008, Murphy 2009). In addition the U.S. national institute of health (NIH) proposed a set of
tests (NIH Toolbox5) for the assessment of motor functioning across the life course (Gershon
et al 2013). Those tests aimed to define a standard set of measures to be used as ‘common currency’ across diverse studies making it easier to compare results (Lara et al 2013).
Recently, we have proposed a minimum set of (bio) markers for the assessment of the
healthy ageing phenotype (HAP) (Lara et al 2013). Physical capability is one of 5 domains
characterising the HAP, and here we have adopted the testing recommendations of the NIH
Toolbox. Specifically the instrumentation of those tests (and others) is a key area of ongoing
work within the LiveWell Programme6, which aims to assess the effect of intervention through
instrumented testing of physical capabilities. The aim of this feasibility study was to test a
methodology to instrument the physical capability assessments for use with a group of healthy
5
www.nihtoolbox.org.
LiveWell is a research programme intended to develop interventions to enhance health and well-being in later
life: www.livewell.ac.uk.
6
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Physiol. Meas. 36 (2015) N71
older adults. We adopted a low-cost single tri-axial accelerometer with algorithms (referred to
here as a body worn monitor, BWM) worn on the lower back to quantify the characteristics of
physical capability. We compared results from the BWM with those obtained using conventional (traditional) subjective techniques to provide a comparison with current methods. We
also quantified a range of postural control and gait characteristics which have shown utility
as measures of healthy ageing and pathology. It is proposed that the new method will provide
an objective and translatable approach to physical capability assessment to compare results of
physical capability outcomes across similar/diverse studies.
2. Materials and methods
2.1. Participant recruitment
Older healthy participants (OHP, 50–70 years) were recruited in the North East of England as
part of a pilot intervention study7 within LiveWell which evaluated internet-based lifestyle interventions in people in the retirement transition (approximately 2 years before/after retirement).
Ethical consent for the project was granted by the Newcastle University Faculty of Medical
Sciences ethics committee (00745/2014) and all participants gave informed written consent.
Participant recruitment was arranged at baseline through large employers on Teesside and on
Tyneside. Testing took place at Newcastle University facilities or at a leisure centre in Redcar.
2.2. Equipment
Each participant wore a low cost (<£100) tri-axial accelerometer-based device8 (figure 1,
dimensions: 2.3 × 3.3 × 0.8 cm, weight 9 g) on the fifth lumbar vertebrae (L5). This location
was chosen to minimise device attachment during instrumented testing while also optimising algorithm usage, i.e. numerous algorithms developed for use on L5. The device was held
in place by double sided tape and Hypafix9. The device recorded at a sampling frequency of
100 Hz (16 bit resolution) and at a range of ±8 g. A trained researcher used a stop watch and
measurement tape (as appropriate) to record outcomes for each physical capability task.
2.3. Experimental protocol
The HAP assessment consisted of the following:
(a)Postural control, standing balance: five tests were performed each lasting 50 s without
shoes, arms folded across their chest while focusing on a wall-mounted fixed point
(target) at a horizontal distance of 1 m. Variations included: (i) flat surface, feet together,
eyes open (FLFTEO), (ii) flat surface, feet together, eyes closed (FLFTEC), (iii) foam
surface10 (50.0 × 41.0 × 6.0 cm), feet together, eyes open (FOFTEO), (iv) foam surface, feet together, eyes closed (FOFTEC) and (v) flat surface, tandem stance, eyes open
(FLTMEO). Due to the nature of the task and derived outcomes (section 2.5) this was
quantified by the BWM only.
(b)Locomotion, 4 m walk gait speed (×2): after a practice walk, participants walked at their
usual speed between two markers. Manual and BWM timing began upon the first footfall,
7
Protocol registered at ClinicalTrials.gov (NCT02136381).
Axivity AX3, York, UK.
9
BSN Medical Limited, Hull, UK.
10
Balance-pad Elite, AIREX, Switzerland.
8
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Figure 1. Attachment of the BWM to the lower back (L5).
i.e. participant’s first step over the starting point. Recording ended after the participant
completed the walk (manual) or last ‘purposeful’ footfall (BWM), i.e. vertical acceleration (aV) exceeded a predetermined threshold. The threshold excluded any non-purposeful
steps after the 4 m marker where the participant had slowed. Time to complete the 4 m
walk was converted into a meters-per-second metric.
(c)Endurance, 2 min walk: participants walked continuously and as fast as they could
without running. The route consisted of walking back and forth around cones placed
25 feet (7.62 m) apart. Once completed, the total distance walked was calculated manually.
(d)Lower limb strength, repeated sit-to-stand-to-sit (×2): after a practice, participants
performed five sit-to-stand-to-sit posture transitions (PT), with arms folded across their
chest, as quickly as possible. Participants were instructed to stand fully and not to touch
the back of the chair during each repetition.
(e)Lower limb strength and locomotion, TUG (×3): after a practice, participants stood up
from a chair (height: 40–50 cm), walked 2 m at a normal pace, around a cone, back to
the chair, turned and sat down. The TUG time was recorded manually as the time from
initiation of chair rise to the time when the participant’s back touched the backrest of the
chair at the end of the manoeuvre.
2.4. BWM algorithms
The following is a brief overview of the algorithms used to instrument each of the tasks outlined in section 2.3:
(a)Algorithm #1 (postural control): jerk (rate of change of aM, equation(1)), root mean
square (RMS, aM magnitude equation (2)) and frequency components (95% percentile
(F95%), ellipsis) were implemented (Moe-Nilssen and Helbostad 2002, Mancini et al
2012). Figure 2(a) shows an example of the data with the segmentation markers to extract
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Figure 2. (a) An example of the tri-accelerometer output during the standing balance
test under the condition of FOFTEO. The red and green vertical dashing lines signify the
start and end times of the tests obtained from observer reported times and which were
used by Matlab to crop the data. (b) An example of the SVM (red) and continuous
peaks (blue) from the DWT detected during a repeated sit-to-stand transition. The
wavelet algorithm identified the transition type and the time between the first (green dot,
sit-to-stand) and last (red dot, stand-to-sit) peak to determine the total time to complete
the task. (c) An example of the SVM (red) and continuous peaks (blue) from the DWT
detected during a TUG test. The wavelet algorithm identified the transition type and
the time between the first (green dot, sit-to-stand) and last (red dot, stand-to-sit) peak
to determine the total time to complete the task. The DWT successfully supressed the
period of walking between transitions.
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the exact period of standing data. Due to its sensitivity, we present acceleration data
within the mediolateral (aM) direction only (Moe-Nilssen and Helbostad 2002).
t
⎛ daM ⎞2
1
⎜
⎟
Jerk
=
(1)
⎝ dt ⎠
2
∫
0
1 2
2 )
RMS
=
(aM1 + ⋯ + aMn
(2)
n
(b)Algorithm #2 (locomotion, endurance): we utilised a Gaussian continuous wavelet transform to estimate the initial contact (IC) and final contact (FC) gait time events from aV
(McCamley et al 2012). From the calculation of IC/FC times, we recorded total time to
complete the 4 m (time between the first IC and last FC). In addition, during the endurance task, we calculated numerous temporal gait characteristics based on the estimated
IC/FC events and their sequence within the gait cycle, i.e. step, stride, stance and swing
times.
(c)Algorithm #3 (locomotion, endurance): we applied the inverted pendulum model to
estimate step length (Zijlstra and Hof 2003) and, from this, calculated the total distance
walked during the endurance task (summation of step lengths). The model is based on the
vertical movement of the centre of mass (h) due to the double integration of aV and length
of the pendulum (l, height of sensor from ground), equation (3).
(3)
step
length = 2 2lh − h2
Algorithm #2 + #3 (locomotion, endurance): the estimates of step time and step length were
combined to generate values for mean step velocity, equation (4).
step length
step velocity
= (4)
step time
(d) Algorithm #4 (lower extremity strength, TUG): timed PT were estimated from a discrete
wavelet transform (DWT, using a fifth-order approximation and Meyer wavelet) of the
signal vector magnitude (SVM) from all three axes of the accelerometer (Bidargaddi et
al 2007). The total time for five PT repetitions was derived from the initial trough (sit-tostand) to the final peak (stand-to-sit), figure 2(b).
This method also estimated total time to complete the TUG. Similar to the lower strength
task the peak and trough of the transitions were used to calculate the time from start to finish,
figure 2(c).
2.5. Statistical analysis
Paired sample t-tests were used to test for differences between manual and BWM quantified
tasks. A repeated measures analysis of variance (ANOVA) with a Greenhouse–Geisser correction was used to examine differences in balance tests. For all analysis, statistical significance
was set at p < 0.05.
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Table 1. Demographic characteristics of the participants.
Characteristic
Mean ± SD
Gender (M/F)
Age
Height (m)
Weight (kg)
7/13
61.4 ± 3.3
1.65 ± 0.09
74.36 ± 14.57
Table 2. Parameter estimates from the standing balance test as quantified by the BWM
(body worn monitor).
Characteristics
Task—test
Trial
Jerk ML
(m2 s−5)
RMS ML
(mm s−2)
Ellipsis
(mm2)
F95%
ML (Hz)
Postural control
(standing balance)
(1) FLFTEO
(2) FLFTEC
(3) FOFTEO
(4) FOFTEC
(5) FLTMEO
0.07 ± 0.16
0.05 ± 0.06
0.33 ± 1.16
0.54 ± 0.62
0.16 ± 0.24
0.01 ± 0.01
0.01 ± 0.00
0.01 ± 0.01
0.03 ± 0.01
0.01 ± 0.01
0.20 ± 0.39
0.16 ± 0.16
0.65 ± 1.63
1.43 ± 1.72
0.28 ± 0.31
1.96 ± 0.64
1.91 ± 0.57
1.78 ± 0.69
1.91 ± 0.53
2.25 ± 0.62
Task 4 was significantly different from the rest. FLFTEO = flat surface feet together eyes open; FLFTEC = flat
surface, feet together, eyes closed; FOFTEO = foam surface, feet together, eyes open, FOFTEC = foam surface, feet
together eyes closed; FLTMEO = flat surface, tandem stance, eyes open.
3. Results
Twenty participants were recruited and their demographics are presented in table 1.
3.1. Postural control
Table 2 shows values for aM for each task. The varying complexity of task from flat to foam
surface is highlighted by the significantly increased RMS (p < 0.000) and Elliptical (p =
0.006) values. Jerk marginally increased between tests (p = 0.072) where greatest differences
are observed between eye closed on flat surface compared to foam. There was no significant
difference between tests for F95% (p = 0.122).
3.2. Locomotion
In trial 1, the BWM had a longer duration (greater) time compared with manual recording
(−0.04 s) but this was not significant (p = 0.682). Mean difference (0.00 s) improved for trial 2
with no significant differences between times (p = 0.981).
3.3. Endurance
The BWM significantly overestimated (p = 0.037) the total distance walked (approx. 11 m or
6.6%) compared with manually recording (table 3). It was also possible to determine additional gait characteristics from the BWM (table 4).
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Table 3. Mean ± SD values for the manual and BWM (body worn monitor) quantified
tasks. Shown are the parametric, non-parametric and ICC tests. (*p < 0.05, **p < 0.001.)
TUG = Timed up and go.
Manual
Task—test
Trial #
Locomotion—gait
speed (m s−1)
Endurance—2 min
walk (m)
Lower extremity
strength—repeated
sit-to-stand-to-sit (s)
Lower extremity strength
and locomotion—TUG (s)
BWM
Mean ± SD
Mean ± SD
1
2
1
1.38 ± 0.14
1.42 ± 0.19
171.19 ± 18.05
1.43 ± 0.43
1.42 ± 0.41
182.54 ± 28.52
0.682
0.981
0.037
1
2
8.06 ± 1.73
7.79 ± 1.73
6.91 ± 1.50
6.77 ± 1.68
0.000
0.000
1
2
3
4.93 ± 0.71
4.87 ± 0.73
4.81 ± 0.69
5.18 ± 2.47
4.47 ± 1.71
4.75 ± 2.29
0.629
0.319
0.905
p
Table 4. Estimates of spatio-temporal gait characteristics obtained from the 2 min
endurance walking test by the BWM (body worn monitor).
Task
Endurance
Gait
characteristic
Step time (s)
Stride time (s)
Stance time (s)
Swing time (s)
Step length (m)
Step velocity
(m s−1)
Result
Mean
Variability
Asymmetry
0.47 ± 0.03
0.94 ± 0.06
0.60 ± 0.04
0.34 ± 0.02
0.70 ± 0.08
1.53 ± 0.21
0.08 ± 0.04
0.12 ± 0.06
0.08 ± 0.04
0.08 ± 0.04
0.11 ± 0.04
0.25 ± 0.08
0.01 ± 0.01
0.00 ± 0.00
0.01 ± 0.01
0.01 ± 0.01
0.01 ± 0.01
0.03 ± 0.04
3.4. Lower limb strength
The BWM had significantly shorter duration (faster) time estimates for repeated PT (by
approx. 1 s for both trials) compared with manual recordings (p < 0.000).
3.5. Lower limb strength and locomotion
There were no significant differences between the BWM and manual recording for the total
time to complete the TUG (p ≥ 0.319).
4. Discussion
This feasibility study reports further developments of our work on the measurement of the
HAP (Lara et al 2013). We present a methodology to objectively quantify physical capability
using a low cost accelerometer-based BWM with a novel combination of algorithms as an
instrumented form of assessment. We were able to demonstrate that there were no significant
differences between the BWM and manual recordings for most tasks suggesting it is a feasible alternative to quantify physical capability. Moreover, the adoption of the standardised
instrumented protocol offers the ability to objectively quantify physical capability and use the
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outcomes in a pooled comparison of results across similar/diverse studies while also yielding
additional sensitive outcomes.
4.1. Postural control
Quantifying balance with a BWM on the lower back has previously been shown to be reliable
and suitable for vestibular impairment screening (Rine et al 2013). Moreover, similar work
has shown accelerometry related outcomes (similar to those derived here) to be better or consistent with centre of pressure outcomes quantified using traditional methods, e.g. force plates
(Whitney et al 2011). Exact comparison to other accelerometer-based postural control data
from the literature is difficult due to the novelty of the work (use of a BWM) and variation
in protocols. The outcomes quantified in this study were similar to other work (Mancini et al
2012) and also showed sensitivity to the difficulty of the protocol as seen previously (Rine
et al 2013). We observed that F95% (ML direction) was the least discriminatory between trials. Therefore its use in HAP testing warrants further investigation.
4.2. Locomotion
This is the first study to utilise the timing sequence of IC/FC within the gait cycle to estimate total time to complete the 4 m walk and hence determine speed. Compared with manual
recordings, the BWM had shorter durations (faster). Slight differences in trial 1 may be due
to the subjective nature of manual recording, i.e. researcher error in timing the beginning/end
of the walk. Conversely, the dependence of the BWM algorithm on identifying the final (purposeful) FC to mark the end of the trial may also impact upon timing error. However, in trial
2, mean difference between methods improved suggesting a learning effect for the observer
and, perhaps, better participant compliance (complete stop after 4 m). One possible method
for improving the FC event estimations is the alternative use of wavelet where it has been suggested that a bi-orthogonal spine wavelet is superior to that used here, i.e. Gaussian (Shao and
Ma 2003). This will be evaluated in future studies.
4.3. Endurance
The pendulum technique overestimated step length and subsequently total distance walked
due to the spatial parameter being sensitive to linear deviations of gait (rounding/turning
the cones) (Zijlstra and Hof 2003). Estimated distance by the BWM may be improved by
introducing a more linear walking route, i.e. limit abrupt turning. We quantified numerous
spatio-temporal gait characteristics to highlight the added benefit of a BWM. While this task
has been recommended by the NIH Toolbox for assessing overall cardiovascular endurance,
the inclusion of a BWM allows researchers to assess the gait characteristics (over a suitable
period) (Galna et al 2013, Lord et al 2013a) which have been shown to be sensitive to age
(Lord et al 2013b) and pathology (Rochester et al 2012) and could prove useful for future
testing. Moreover, the quantified gait characteristics presented here are similar to other studies
that used an instrumented walkway (Senden et al 2009, Hollman et al 2011, Lord et al 2013b,
Kobsar et al 2014b). However, notable difference are observed for the variability of all gait
characteristics which is similar to other work (Kobsar et al 2014a). This can be attributed to
the functional differences between systems (pressure sensor versus continuous tracking of a
body and its acceleration through space) and drift due to integration (Hartmann et al 2009).
However, this approach offers another important dimension to the endurance task which will
be investigated in future HAP work within LiveWell.
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4.4. Lower limb strength
This is the first study to use the wavelet algorithm to quantify repeated PT as it has been specifically designed for individual sit-to-stand and stand-to-sit transitions only. The mean times
had a significantly shorter duration (faster) for the BWM compared to manual recordings
(p < 0.000). This could be due to observer variability in recording the start and finish times of
the transitions which can be difficult to achieve due to participant performance. Other factors
that may impact on calculations include BWM time to complete repeated PT, taken as the time
between first and last peaks, figure 2(b). Methodologically the correct timing sequence for a
single transition is the time between successive peak/trough or trough/peak ×2 (Bidargaddi
et al 2007). Multiplication by the correction factor of 2 was excluded here due to the nature
of the task, i.e. a continuous sequence of sit-to-stand-to-sit. The adaptation of the algorithm to
include a correction <2 may help refine the slight timing anomaly, which appears systematic
in nature, figure 3(a). To test this hypothesis, we calculated a new correction factor for future
use with this algorithm during repeated PT. Based on the percentage difference between both
methods we computed and subsequently recommend a value of 1.16. When applied to BWM
values and compared to those from manual recordings, no significant differences were found
(p ≥ 0.603), figure 3(b).
Furthermore, the shorter duration PT estimates by the BWM compared to manually
recorded times can be attributed to algorithm functionality due to BWM location and definition of PT (Godfrey et al 2014). This is because the algorithm is best suited to estimation of
the dominant vertical rise (DVR) transition whereas momentum transfer is quantified by the
visual observation of the researcher and that which is normally adopted by OHP (Scarborough
et al 2007). However, due to its mechanics the DVR may be a good proxy for assessing lower
extremity strength within this task but remains untested (Godfrey et al 2014). Change of sensor location (chest) to suit the momentum transfer strategy is likely to improve agreement
but impact negatively on the ability to holistically and accurately quantify the subdomain of
physical capability outlined in this study (Godfrey et al 2014).
4.5. Lower limb strength and locomotion
There were no significant differences between times quantified by the BWM and observer
although the BWM had (generally) shorter durations in comparison to manual recordings.
This could be explained by the algorithm adopted to quantify PT (exclusion of the correction
factor) and the PT strategy adopted (see discussion above, section 4.4). However, this is the
first time that the wavelet algorithm has been used to quantify the TUG test and it performed
well in recognising the PT at the beginning/end of the task as well as suppressing the walk and
turning components of aV, figure 2(c). Slight differences by the BWM can be attributed to the
nature of the composite task (sit-to-stand, walk, turn, walk, turn and stand-to-sit), which may
negatively impact on the peak detection accuracy and hence timing. Segmenting the task into
its various components with the summation of their individually timed sections may improve
results, though this is only attainable with the use of a gyroscope (Salarian et al 2010).
5. Conclusion
This study explores the feasibility of a methodological approach to objectively quantify physical capability within the HAP by using a single low-cost BWM. Comparative analysis with
manual observation demonstrated that a BWM is a suitable and objective measure to quantify
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Figure 3. (a) Scatter plot of repeated sit-to-stand-to-sit PT showing the systematic
shorter duration (faster) nature of times as quantified by the BWM. (b) After a
correction factor of 1.16 was applied there was no significant difference between BWM
and manual recording. (Participant times arranged from lowest to highest for clarity.)
postural control, locomotion, lower limb strength (with new correction factor of 1.16) and
lower limb strength and locomotion. Though the BWM overestimated total distance, gait
characteristics derived during this test may prove more useful in future tests. As a result, the
method presented here should be a focus of constant re-evaluation to ensure ‘fit-for-purpose’
equipment and techniques. Our findings suggest that the use of a BWM can provide the basis
for a more objective and transferrable depiction of capability which has practical implications
for instrumented testing in large scale interventions and could also be extended to studies
involving pathology. It also serves to limit the potential for ‘human-error’ through adoption
of algorithmic analysis, and provides the added dimension of novel postural control outcomes
and gait characteristics during the endurance task. Future work will involve refinement of the
methodology for large scale deployment within the LiveWell to assess the effect of intervention through instrumented testing.
Conflict of interest
There is no conflict of interest.
Funding
Authors acknowledge support from the LiveWell program a research project funded through
a collaborative grant from the lifelong health and wellbeing (LLHW) initiative, managed by
the medical research council (MRC) on behalf of the funders: Biotechnology and Biological
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Sciences Research Council, Engineering and Physical Sciences Research Council, Economic
and Social Research Council, Medical Research Council, Chief Scientist Office of the
Scottish Government Health Directorates, National Institute for Health Research (NIHR)/The
Department of Health, The Health and Social Care Research and Development of the Public
Health Agency (Northern Ireland), and Wales Office of Research and Development for Health
and Social Care and the Welsh Assembly Government (grant number: G0900686). LR and
AG are supported by the national institute for health research (NIHR) Newcastle Biomedical
Research Centre and Unit based at Newcastle upon Tyne Hospitals NHS Foundation Trust and
Newcastle University. The views expressed are those of the authors and not necessarily those
of the NHS or NIHR or the Department of Health. SDD is supported by the V-Time project,
which is a European Union 7th Framework Programme (FP7) under the Health theme (FP7:
278169).
Acknowledgments
The authors thank those who participated in the study.
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